Regulation Little League games last six innings. Tokyo Kitasuna Little League needed just one to assert its dominance on the final day of the 2012 Japanese Region tournament.

Tokyo Kitasuna scored twelve times in the first inning of a 14-4 semifinal round victory over Funabashi Little League, and then tallied ten runs in the opening frame of an 11-0 win over Matsusaka Little League at Edogawa-Ku Stadium near Tokyo. The two mercy rule-shortened victories propelled the Japanese champions into the Little League World Series for the third time in eleven years. Tokyo Kitasuna eventually defeated Goodlettsville Baseball Little League (Tennessee) by a 12-2 score to win the 2012 Little League World Series championship.

Pitchers Yuta Ishida and Kotaro Kiyamiya each threw a pair of complete game victories in Tokyo Kitasuna's sweep at the sixteen-team Japanese championship tournament. Ishida surrendered just a pair of runs in an 8-2 opening round win over Ueda Minami Little League, and Kiyomiya threw a four inning shutout against Iwakitaira Little League on the tournament's first day. One week later, when the four quarterfinal round winners reconvened in Tokyo for the semifinal and championship rounds, Ishida allowed three first inning runs, but settled down and allowed just one run over the next three innings of the win over Funabashi. Kiyomiya then collected his second shutout as Tokyo Kitasuna blitzed Matsusaka in the championship game.

Leadoff hitter Noriatsu Osaka propelled Tokyo Kitasuna to its semifinal round win with a pair of home runs, while catcher Tatsuya Irie and Satoru Aoyama also homered for the Tokyo champions. Osaka and Kiyomiya had homered in both of Tokyo Kitasuna's opening day victories, while Aoyama and Shun Oshima also homered in the win over Iwakitaira.

Matsusaka, which returned to the Japanese championships after a quarterfinal round finish in 2011, reached the championship game by overwhelming Sendai Higashi Little League, 20-10, in the other semifinal round game. Sendai elected to hold pitcher Ito Saeki, who had thrown an eighteen strikeout shutout in his team's 1-0 opening round win over Hiroshima Saiki Little League, with an eye toward a potential championship round meeting with Tokyo Kitasuna. But Matsusaka spoiled the Sendai plan, homering five times and breaking the game open with five runs in the fourth inning and eight more in the sixth.

Tokyo Kitasuna, which was heavily favored in the region tournament on the heels of their victory in the Kanto Cup tournament earlier in the year, avoided a second pitcher being held for it in its quarterfinal round contest. Sasebo Chuo Little League elected to bypass its ace pitcher in an opening round draw against Iwakitaira, knowing that a potential matchup with Tokyo Kitasuna likely loomed should they win their opening round game. Sasebo's pitcher had struck out seventeen in the All-Kyushu tournament championship game, but Iwakitaira ended Sasebo's tournament run by winning the teams' opening round game in the Japanese championship tournament by a 3-2 score.

Tokyo Kitasuna's championship game victory gave the league and longtime manager Yoichi Kubo its third-ever Japanese championship. Eight weeks later, the Japanese winners became the ninth league to claim multiple Little League World Series championships with their victory over Goodlettsville in the Little League World Series championship game in South Williamsport, Pennsylvania. Tokyo Kitasuna won the 2001 Little League World Series, and finished as the runner-up to Warner Robins American (Georgia) Little League in 2007.